diff --git a/inc/caldav-MKCALENDAR.php b/inc/caldav-MKCALENDAR.php
index eccb27b1..18a8a528 100644
--- a/inc/caldav-MKCALENDAR.php
+++ b/inc/caldav-MKCALENDAR.php
@@ -10,10 +10,6 @@
 */
 dbg_error_log("MKCALENDAR", "method handler");
 
-dbg_log_array( "MKCOL", 'HEADERS', $raw_headers );
-dbg_log_array( "MKCOL", '_SERVER', $_SERVER, true );
-dbg_error_log( "MKCOL", "RAW: %s", str_replace("\n", "",str_replace("\r", "", $raw_post)) );
-
 $make_path = $_SERVER['PATH_INFO'];
 
 $displayname = $make_path;
@@ -22,6 +18,18 @@ if ( preg_match( '#^(.*/)([^/]+)(/)?$#', $make_path, $matches ) ) {
   $parent_container = $matches[1];
   $displayname = $matches[2];
 }
+$sql = "SELECT * FROM collection WHERE user_no = ? AND dav_name = ?;";
+$qry = new PgQuery( $sql, $session->user_no, $make_path );
+if ( ! $qry->Exec("MKCALENDAR") ) {
+  header("HTTP/1.1 500 Infernal Server Error");
+  dbg_error_log( "ERROR", " MKCALENDAR Failed (database error) for '%s' named '%s', user '%d' in parent '%s'", $make_path, $displayname, $session->user_no, $parent_container);
+  exit(0);
+}
+if ( $qry->rows != 0 ) {
+  header("HTTP/1.1 412 Calendar Already Exists");
+  dbg_error_log( "ERROR", " MKCALENDAR Failed (already exists) for '%s' named '%s', user '%d' in parent '%s'", $make_path, $displayname, $session->user_no, $parent_container);
+  exit(0);
+}
 
 $sql = "INSERT INTO collection ( user_no, parent_container, dav_name, dav_etag, dav_displayname, is_calendar, created, modified ) VALUES( ?, ?, ?, ?, ?, TRUE, current_timestamp, current_timestamp );";
 $qry = new PgQuery( $sql, $session->user_no, $parent_container, $make_path, md5($session->user_no. $make_path), $displayname );
@@ -32,48 +40,49 @@ if ( $qry->Exec("MKCALENDAR",__LINE__,__FILE__) ) {
 }
 else {
   header("HTTP/1.1 500 Infernal Server Error");
-  dbg_error_log( "ERROR", " MKCOL Failed for '%s' named '%s', user '%d' in parent '%s'", $make_path, $displayname, $session->user_no, $parent_container);
+  dbg_error_log( "ERROR", " MKCALENDAR Failed for '%s' named '%s', user '%d' in parent '%s'", $make_path, $displayname, $session->user_no, $parent_container);
+  exit(0);
 }
 
 /**
-* We could also respond to the request...
+* FIXME: We could also respond to the request...
+*
+*   <?xml version="1.0" encoding="utf-8" ?>
+*   <C:mkcalendar xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+*     <D:set>
+*       <D:prop>
+*         <D:displayname>Lisa's Events</D:displayname>
+*         <C:calendar-description xml:lang="en">Calendar restricted to events.</C:calendar-description>
+*         <C:supported-calendar-component-set>
+*           <C:comp name="VEVENT"/>
+*         </C:supported-calendar-component-set>
+*         <C:calendar-timezone><![CDATA[BEGIN:VCALENDAR
+*   PRODID:-//Example Corp.//CalDAV Client//EN
+*   VERSION:2.0
+*   BEGIN:VTIMEZONE
+*   TZID:US-Eastern
+*   LAST-MODIFIED:19870101T000000Z
+*   BEGIN:STANDARD
+*   DTSTART:19671029T020000
+*   RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+*   TZOFFSETFROM:-0400
+*   TZOFFSETTO:-0500
+*   TZNAME:Eastern Standard Time (US & Canada)
+*   END:STANDARD
+*   BEGIN:DAYLIGHT
+*   DTSTART:19870405T020000
+*   RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
+*   TZOFFSETFROM:-0500
+*   TZOFFSETTO:-0400
+*   TZNAME:Eastern Daylight Time (US & Canada)
+*   END:DAYLIGHT
+*   END:VTIMEZONE
+*   END:VCALENDAR
+*   ]]></C:calendar-timezone>
+*       </D:prop>
+*     </D:set>
+*   </C:mkcalendar>
 *
-   <?xml version="1.0" encoding="utf-8" ?>
-   <C:mkcalendar xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
-     <D:set>
-       <D:prop>
-         <D:displayname>Lisa's Events</D:displayname>
-         <C:calendar-description xml:lang="en">Calendar restricted to events.</C:calendar-description>
-         <C:supported-calendar-component-set>
-           <C:comp name="VEVENT"/>
-         </C:supported-calendar-component-set>
-         <C:calendar-timezone><![CDATA[BEGIN:VCALENDAR
-   PRODID:-//Example Corp.//CalDAV Client//EN
-   VERSION:2.0
-   BEGIN:VTIMEZONE
-   TZID:US-Eastern
-   LAST-MODIFIED:19870101T000000Z
-   BEGIN:STANDARD
-   DTSTART:19671029T020000
-   RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
-   TZOFFSETFROM:-0400
-   TZOFFSETTO:-0500
-   TZNAME:Eastern Standard Time (US & Canada)
-   END:STANDARD
-   BEGIN:DAYLIGHT
-   DTSTART:19870405T020000
-   RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
-   TZOFFSETFROM:-0500
-   TZOFFSETTO:-0400
-   TZNAME:Eastern Daylight Time (US & Canada)
-   END:DAYLIGHT
-   END:VTIMEZONE
-   END:VCALENDAR
-   ]]></C:calendar-timezone>
-       </D:prop>
-     </D:set>
-   </C:mkcalendar>
-
 */
 
 ?>
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